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Dick Smith Memorial Invitational - PA — Forensics

Forensics · Division C · Dick Smith Memorial Invitational - PA · 2026

98 questions · 98 points · 50 min· 3 questions from the original omitted

Original test source

Question 1

1 pt

A white powder reacts vigorously with HCl, producing rapid fizzing. Identify it.

Question 2

1 pt

A powder forms a thick gel when mixed with water. Identify it.

Question 3

1 pt

A powder turns Benedict’s reagent orange. Identify it.

Question 4

1 pt

A powder dissolves endothermically and is strongly basic (pH 11). Identify it.

Question 5

1 pt

A powder is insoluble, gritty, and turns dark blue with iodine. Identify it.

Question 6

1 pt

A powder does not react with vinegar and leaves a white residue when heated. Identify it.

Question 7

1 pt

A powder burns with a bright red flame. What salt is likely?

Question 8

1 pt

A powder gives a purple flame. Identify the cation.

Question 9

1 pt

A powder dissolves easily and smells slightly sweet. Identify it.

Question 10

1 pt

A sample sizzles weakly with vinegar, gives minimal fizz, and shows a pH of 8. Identify it.

Question 11

1 pt

A white powder sample is heated strongly and then tested with HCl. Before heating, it produces vigorous bubbling. After heating, it no longer bubbles with HCl. What is the most likely identity of the powder?

Question 12

1 pt

A mystery white crystalline solid dissolves readily in water, does not react with iodine, and gives a caramel scent when heated. What is it most likely?

Question 13

1 pt

A white powder dissolves slowly in water, forms a strongly basic solution (pH ~12), and gives off heat when dissolved. What is the best match?

Question 14

1 pt

A powder forms a cloudy mixture that thickens upon heating but never fully dissolves. Which is it most likely?

Question 15

1 pt

A clear liquid smells acidic and turns pH paper orange. Identify it.

Question 16

1 pt

A liquid smells like rubbing alcohol and removes sharpie ink. Identify it.

Question 17

1 pt

A liquid is flammable, evaporates fast, and leaves no residue. Identify it.

Question 18

1 pt

A colorless liquid conducts electricity, has no smell, and forms crystalline cubes after evaporation. Which is it?

Question 20

1 pt

A liquid tests positive with Benedict’s reagent. What does it contain?

Question 21

1 pt

Which liquid remains conductive (contains ions) when tested with a conductivity probe?

Question 22

1 pt

A clear liquid evaporates quickly, leaves no residue, and dissolves permanent-marker ink. Its boiling point is measured at ~82°C. What is it?

Question 23

1 pt

A metal reacts strongly with HCl producing rapid bubbles. Identify it.

Question 24

1 pt

A metal shavings sample reacts very slowly with HCl unless it is scratched first, after which the reaction becomes vigorous. What explains this?

Question 25

1 pt

A metal reacts with HCl to produce bubbles and a pale green solution that later forms reddish-brown particles. What metal is this?

Question 26

1 pt

A metal does not react with HCl and is reddish-brown. Identify it.

Question 27

1 pt

A soft, dull gray metal reacts slowly with acid. Identify it.

Question 28

1 pt

A metal produces hydrogen gas slowly and has a dark gray oxide layer. Identify it.

Question 29

1 pt

Which metal is shiny, light, and reacts vigorously with acid?

Question 30

1 pt

Define “Rf value.”

Question 31

1 pt

A chromatography strip shows three pigments (yellow, blue, green). What type of pen is likely?

Question 32

1 pt

A dye shows nearly the same Rf in water but a much lower Rf in isopropanol. What does this imply?

Question 33

1 pt

A chromatogram shows streaking rather than clean circular spots. What is the most likely cause?

Question 34

1 pt

Calulate the Rf value for the highest spot.

Question 35

1 pt

A chromatography sample shows a single black band that does not separate. Identify the pen type.

Question 36

1 pt

Why should the solvent line never cover the ink starting point?

Question 37

1 pt

Why is pencil used instead of pen to draw the origin line?

Question 38

1 pt

What is chromatography used for?

Question 39

1 pt

A pigment on the suspect’s pen matches the crime scene Rf values. What does this indicate?

Question 40

1 pt

A fiber melts, smells like burning hair. Identify it.

Question 41

1 pt

A plastic sample burns with sooty black smoke and drips while burning. Which polymer is this?

Question 42

1 pt

A plastic sample sinks in water, softens with heat, and releases sharp-smelling fumes when burned. Which polymer is likely?

Question 43

1 pt

A fiber melts rapidly and forms a hard bead. Identify it.

Question 44

1 pt

A polymer floats in water and feels waxy. Identify it.

Question 45

1 pt

A rigid plastic that sinks and is used in pipes. Identify it.

Question 46

1 pt

A fiber smells like burning paper. Identify it.

Question 47

1 pt

Which polymer shrinks when heated (shrink wrap)?

Question 48

1 pt

Which polymer is commonly used in water bottles?

Question 49

1 pt

Why are fibers considered “class evidence”?

Question 50

1 pt

A hair with thick medulla and coarse texture is:

Question 51

1 pt

Human hair with a continuous medulla is:

Question 52

1 pt

A hair sample shows a fragmented medulla, uniform pigment distribution, and a thin cuticle. Which type of hair is it?

Question 53

1 pt

A hair root is spade-shaped, and the shaft shows a thick continuous medulla. What animal is this typical of?

Question 54

1 pt

Why can’t hair specify an individual?

Question 55

1 pt

Name the differences between human and animal hair.

Question 56

1 pt

A fingerprint with one delta is a:

Question 57

1 pt

Two deltas and circular ridges indicate a:

Question 58

1 pt

No deltas indicate a:

Question 59

1 pt

Which pattern is most common?

Question 60

1 pt

Which method is MOST appropriate for visualizing a latent fingerprint on notebook paper?

Question 61

1 pt

A fingerprint shows two deltas, but the core appears strongly offset from the line between them. What pattern is this?

Question 62

1 pt

Which chemical is used to reveal prints on porous surfaces like paper?

Question 63

1 pt

Which powder is used on dark, nonporous surfaces?

Question 64

1 pt

Why are fingerprints considered individual evidence?

Question 65

1 pt

What is a minutiae point?

Question 66

1 pt

What is density used for in glass analysis?

Question 67

1 pt

A bullet hole has wider radial cracks on one side. Which side was struck?

Question 68

1 pt

A glass fragment shows the Becke line moving into the glass when the microscope stage is lowered. What does this mean?

Question 69

1 pt

Concentric fractures terminate at radial fractures in a windowpane. What does this indicate?

Question 70

1 pt

How is refractive index used to compare glass samples?

Question 71

1 pt

What is the “Becke line”?

Question 72

1 pt

Soil with sand, clay, and organic matter is called:

Question 73

1 pt

A soil sample with high clay content will feel:

Question 74

1 pt

Which soil type drains the fastest?

Question 75

1 pt

A soil sample contains high organic matter, medium clay, and excellent water retention. Where is it most likely from?

Question 76

1 pt

A soil sample contains mostly quartz, is tan-colored, and has very low clay content. Most likely origin?

Question 77

1 pt

Which suspect matches the crime scence?

Question 78

1 pt

A ____ charge is used to move DNA through the gel and ____ fragments will travel farther.

Question 79

1 pt

A DNA electrophoresis gel shows severely smeared bands. Which is the most likely cause?

Question 80

1 pt

A DNA STR profile shows allele dropout only at one locus. What is the most common cause?

Question 81

1 pt

Why are multiple loci used in DNA profiling?

Question 82

1 pt

What is the DNA ladder used for?

Question 83

1 pt

Blowfly eggs are found; temperature is 25°C. Time since death?

Question 84

1 pt

Which insect typically arrives first at a corpse?

Question 85

1 pt

A body is found with empty puparial cases and both adult flies and beetle larvae present. What is the most likely PMI?

Question 86

1 pt

Insect development is delayed beyond expected thermal calculations. What could explain this?

Question 87

1 pt

Name major environmental factors affecting insect development.

Question 88

1 pt

Why is entomology useful in forensics?

Question 89

1 pt

What does IR spectroscopy identify?

Question 90

1 pt

What does GC-MS stand for?

Question 91

1 pt

What does the MS provide?

Question 92

1 pt

A GC-MS spectrum shows one tall peak and an intact molecular ion with minimal fragmentation. What does this suggest?

Question 93

1 pt

An IR spectrum shows a sharp C=O peak near 1700 cm⁻¹ and a very broad O–H peak. What functional group is present?

PassageFor questions 95–100

Case Background

At first, many residents of Allenville celebrated the election of Robert Burlington as mayor. Burlington had grown up in the rural, working-class town. He went off to college, married, and eventually returned to Allenville, becoming a partner in a struggling local investment firm. As a candidate, Burlington promised to make Allenville a great place to live and work. He ran against incumbent mayor Timothy Taylor, who tried to maintain the sleepy image of Allenville. Though a number of people spoke out against him during the campaign (including local environmentalist Pam Preston), Burlington won by a narrow margin.

Within a year, however, rumors began to circulate that Burlington was taking bribes from businessmen lobbying to build an industrial park in Allenville. The proposed industrial site was home to a few small businesses and a wilderness area called Lake Larson Park. Burlington did in fact support the industrial park, and he argued that a new road should be built to access it. If approved, the project would destroy much of the forested area surrounding Lake Larson Park as well as some adjacent farmland. The local newspaper published editorials accusing the mayor of destroying small businesses, the environment, and the tourist trade. Concerned citizens Matthew Maloy and Vic Velto started a petition to remove the mayor from office, but failed to get enough signatures. Shortly thereafter, the mayor was seen having a heated and very public argument with his wife, Nicole. The following day, observant citizens saw Nicole Burlington driving through town in a new car and wearing an expensive fur coat.

The last town council meeting held before Burlington's death was a nightmare for residents. A critical vote to annex the land for the industrial park and for approval of the connecting road was coming up in three days. Burlington had thus far bullied the town council into approving his plans, and many felt that Allenville would be forever changed by the results of the upcoming meeting. In front of the town council, the mayor dismissed his opponents' criticism as "small-town thinking" and stated that he was on a mission to make Allenville more prosperous. When residents objected, Burlington angrily replied that he was the mayor and that no one in town could stop him. At this point in the proceedings, councilman Chris Cunningham publicly accused the mayor of lying and taking bribes. The mayor abruptly ended the meeting and stormed out of the building as the town hall erupted into chaos.

One day before the planned town council vote, Nicole Burlington reported her husband missing. She claims that he told her he was going to "a silly meeting," but he never returned. Five days after the town council meeting, Burlington's car was found on an unpaved, isolated road near Lake Larson. The mayor was not there, but his keys were in the ignition. Several drops of blood were found on the front seat. A tire iron, smudged with blood, was found in the woods near the car. A second set of tire tracks was found near the mayor's car. The tracks followed a muddy road to a deserted cabin deeper in the woods.

Entering the cabin, the investigators immediately knew they were looking at a crime scene. A glass window was shattered and the furniture in the cabin was scattered and broken, suggesting a struggle had taken place. Mayor Robert Burlington lay on his side, a single bullet hole in his chest. He also had a large wound on the back of his head. It was apparent that he had been dead for a while; the stench of decay was present and maggot activity was evident on the body.

The investigators gathered five different types of evidence for comparison and further analysis as described below.

  1. Entomological Evidence. Investigators collected insect larvae (maggots) from the victim's head and chest wound sites. This evidence is useful in conjunction with the alibi interviews of the murder suspects.
  2. Hair Evidence. Investigators collected samples of hair from the victim's clothing, the victim's car, and the cabin floor. Later, they collected and analyzed hair samples from the six suspects' vehicles.
  3. Blood Evidence. Investigators collected samples of blood from the victim, the victim's car, the cabin floor, and the tire iron. Later, they collected blood samples from the six suspects.
  4. Fingerprint Evidence. Investigators obtained fingerprint samples from the victim, from a piece of broken glass in the cabin, from a bloodstained piece of wood in the cabin, and from the tire iron. Later, they collected fingerprint samples from the six suspects.
  5. Impression Evidence. Investigators photographed the tire impression found at the cabin crime scene. Later, they photographed the tires of vehicles belonging to the six suspects.

Question 95

1 pt

Given the average length of the blow flies found on the body, what is the estimated days since death?

Question 96

1 pt · select all that apply

Police detectives interviewed all six suspects and recorded their alibis for the last eleven days. The investigators were able to confirm some but not all of the suspects' alibis. The following table is a summary of their results. A confirmed alibi (C) means that the suspect's whereabouts at the time are known, and therefore he or she could not have committed the murder on that day. An unconfirmed alibi (U) means that the suspect's alibi for that day could not be verified, and therefore he or she could potentially have committed the murder on that day.

Based on this information, which suspects could have committed the crime? Select all that apply.

Question 97

1 pt · select all that apply

An important concept in forensic science is the Locard Exchange Principle, which states that every contact between two objects results in an exchange of physical materials. According to the sample above, which suspects could have come into contact with the victim recently? Select all that apply.

Question 98

1 pt · select all that apply

Based on the blood evidence above, which suspects could have committed the crime? Select all that apply.

Question 99

1 pt · select all that apply

Based on the impression evidence above, which suspects could have committed the crime? Select all that apply.

Question 100

1 pt · select all that apply

Based on the above fingerprints, which of the suspects were at the crime scene? Select all that apply.